Rotary internal combustion engines of the "rat-race" or "cat-and-mouse" variety are known to the art. See Chinitz, W., "Rotary Engines", Scientific American, Vol. 220, No. 2 (1969). A major problem associated with these "scissor-action" type engines lies in the high inertial forces generated as the pistons are alternately accelerated and decelerated to generate four-cycle operation. Some designs involve complex crank and gear designs, e.g., Arnal U.S. Pat. No. 3,500,798, complex pin and slot arrangements, e.g., Bancroft U.S. Pat. No. 2,553,954, a sprag assembly in conjuction with a roller wedging mechanism, e.g., Sinnott U.S. Pat. No. 3,282,258 or a hinged pawl-roller assembly which tracks a rotor positioning profile, e.g., Bartolozzi U.S. Pat. No. 3,227,090. Each of these references is either mechanically complex or results in an abrupt change of piston velocity.
Accordingly, it is an object of the invention herein to provide a rotary device that may be used as a rotary internal combustion engine or a rotary pump which is mechanically simple and which provides for smooth acceleration, deceleration and locking of alternating pistons in a "scissor-action" engine.